How to install VB-Cable on Windows and route demodulated audio from SDR software like SDRUno and SDRconnect to digital decoders — while still hearing it through your speakers.
VB-Cable is a free virtual audio driver for Windows developed by VB-Audio Software. It creates a virtual audio cable inside your operating system: whatever audio is sent to the CABLE Input (playback device) comes out of the CABLE Output (recording device). No physical cable, no external hardware — just a digital pipe between two applications.
In the SDR world, this is essential. When you demodulate a signal in SDRUno or SDRconnect, the resulting audio needs to reach a decoder application (WSJT-X, fldigi, MultiPSK, DSD+, etc.) in digital form, with zero quality loss. VB-Cable provides exactly that bridge.
VB-Cable is donationware — fully functional for free, with an optional donation. If you need more than one virtual cable, VB-Audio offers additional pairs (A+B and C+D) for a small donation.
Before you begin, make sure you have the following:
| Requirement | Details |
|---|---|
| Windows | Windows 10 or 11 (64-bit recommended) |
| Admin rights | The installer must be run as Administrator |
| SDR software | SDRUno and/or SDRconnect installed and working |
| Decoder | Any application that accepts audio input (WSJT-X, fldigi, DSD+, etc.) |
Go to the official VB-Audio website and download the VB-Cable driver package:
The download is a .zip archive named something like VBCABLE_Driver_Pack45.zip. Save it to a known location on your system drive (e.g. your Desktop or Downloads folder).
Right-click the downloaded .zip file and select Extract All... to unpack its contents into a folder. Inside you will find the setup executable and some documentation files.
This is critical. Right-click on VBCABLE_Setup_x64.exe (for 64-bit Windows) and select Run as administrator. If you are on a 32-bit system, use VBCABLE_Setup.exe instead.
Click Install Driver when prompted. The installation is very quick — you will see a confirmation message when it completes.
You must run the installer as Administrator. If you don't, the driver will not be registered correctly in Windows and the virtual audio device will not appear.
After installation, reboot your PC. This is mandatory — the virtual audio driver needs a restart to be properly registered in the Windows audio subsystem.
After rebooting, you need to confirm that VB-Cable was installed correctly. Open the Windows Sound settings by right-clicking the speaker icon in the taskbar and selecting Sound settings, then scroll down and click More sound settings to open the classic Sound control panel.
In the Playback tab, you should see a new device called CABLE Input (VB-Audio Virtual Cable). This is the "input side" of the virtual cable — whatever audio you send here will travel through the cable.
In the Recording tab, you should see CABLE Output (VB-Audio Virtual Cable). This is the "output side" — the receiving application will pick up audio from this device.
Make sure your default playback device is still set to your speakers or headphones — not to VB-Cable. If you accidentally set VB-Cable as the default playback device, you will lose all system audio through your speakers.
If VB-Cable does not appear after rebooting, check that Windows Privacy settings for the microphone are enabled. Windows treats VB-Cable Output as a "microphone" device, and if microphone access is disabled globally or for specific apps, those apps won't be able to use VB-Cable as an input source.
SDRUno allows you to select any audio device as its output. Instead of sending the demodulated audio to your speakers, you redirect it to VB-Cable so that a decoder application can receive it digitally.
In SDRUno, click the SETT. button on the top left of the RX Control panel. This opens the settings dialog for the receiver.
Click on the OUT tab. Here you can change the audio output device that SDRUno uses for the demodulated signal.
From the output device dropdown, select CABLE Input (VB-Audio Virtual Cable).
In your decoder application (WSJT-X, fldigi, DSD+, etc.), go to its audio settings and select CABLE Output (VB-Audio Virtual Cable) as the audio input device.
The audio chain is now complete: SDRUno demodulates the signal, sends it through VB-Cable, and the decoder picks it up on the other end.
When you set SDRUno's output to VB-Cable, you will no longer hear the audio through your speakers. This is normal — the audio is being routed to the virtual cable instead. See Section 07 for how to hear it through your speakers at the same time.
SDRconnect, the newer SDR application from SDRplay, also supports selecting a custom audio output device. The process is similar to SDRUno but the interface is slightly different.
In SDRconnect, click the gear icon (Device Settings) on the main toolbar. This opens the settings panel where you can configure input, gain, and audio output options.
Look for the Audio Output device selector. By default it is set to your system's default speakers. Change it to CABLE Input (VB-Audio Virtual Cable).
If the dropdown does not show VB-Cable, make sure you have rebooted after installation and that the virtual cable appears in the Windows Sound settings.
Just like with SDRUno, open your decoder application and set its audio input to CABLE Output (VB-Audio Virtual Cable).
SDRconnect supports multiple Virtual Receivers (VRX). Each VRX can have its own audio output device. If you are using multiple VRXs, you can send one to VB-Cable for decoding and keep another on your speakers for monitoring — no need for the "Listen to this device" workaround described in the next section.
When you redirect the SDR output to VB-Cable, the audio goes exclusively to the virtual cable and you won't hear it from your speakers or headphones anymore. This is the expected behavior — VB-Cable is just a pipe between two apps, not a splitter.
However, Windows has a built-in feature called "Listen to this device" that lets you mirror the VB-Cable output to your speakers, so you can hear the demodulated audio and send it to a decoder at the same time.
Right-click the speaker icon in the Windows taskbar, select Sound settings, scroll down and click More sound settings to open the classic Sound control panel. Alternatively, press Win + R, type mmsys.cpl and press Enter.
Go to the Recording tab. Find CABLE Output (VB-Audio Virtual Cable), right-click it and select Properties.
In the Properties window, click the Listen tab. Check the box Listen to this device.
In the "Playback through this device" dropdown, select your speakers or headphones (e.g. Speakers (Realtek High Definition Audio) or whatever your physical audio output is).
Click Apply, then OK.
Now the audio flows in two directions simultaneously: through VB-Cable to the decoder, and via the Windows "Listen" feature to your speakers. You can monitor what the decoder is receiving in real time.
The "Listen to this device" feature introduces a small amount of latency, since the audio passes through the Windows audio mixer. This is perfectly fine for monitoring purposes but should not be used in latency-critical scenarios.
Alternative approach with SDRconnect: If you are using SDRconnect, you can avoid the "Listen to this device" workaround entirely. Create two Virtual Receivers (VRX) tuned to the same frequency: set one's audio output to VB-Cable for decoding, and the other's output to your speakers for monitoring.
Make sure you ran the installer as Administrator and rebooted your PC after installation. If it still does not appear, try uninstalling and reinstalling the driver, making sure to reboot between each step.
Double-check that the SDR software output is set to CABLE Input (not CABLE Output) and the decoder input is set to CABLE Output (not CABLE Input). The naming can be confusing: "Input" means audio goes into the cable, "Output" means audio comes out of the cable.
| Device Name | What it does | Where to use it |
|---|---|---|
| CABLE Input | Receives audio into the cable | Set as output in SDR software |
| CABLE Output | Delivers audio from the cable | Set as input in decoder app |
Make sure the sample rates match. Open the VB-Cable properties in both the Playback and Recording tabs and set them to the same sample rate (e.g. 48000 Hz). Some SDR and decoder applications also have their own sample rate settings — keep them consistent.
Windows treats the CABLE Output as a "microphone" device. If you have disabled microphone access in Settings → Privacy → Microphone, your decoder apps won't be able to use VB-Cable. Make sure microphone access is enabled for the apps you need.
Verify that the "Playback through this device" dropdown is set to your actual speakers/headphones, not to "Default Playback Device" (which might point to VB-Cable itself if it was accidentally set as default). Also confirm that the speaker device is not muted in the Windows volume mixer.
If you need more complex audio routing — for example, sending audio to multiple decoders simultaneously or mixing sources together — consider Voicemeeter (also by VB-Audio). It's a free virtual audio mixer that provides multiple inputs and outputs with full routing control.